CN109596873B - Smart electric meter with early warning function - Google Patents
Smart electric meter with early warning function Download PDFInfo
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- CN109596873B CN109596873B CN201811482548.9A CN201811482548A CN109596873B CN 109596873 B CN109596873 B CN 109596873B CN 201811482548 A CN201811482548 A CN 201811482548A CN 109596873 B CN109596873 B CN 109596873B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
- G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
- G01R22/061—Details of electronic electricity meters
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Abstract
The invention discloses an intelligent ammeter with an early warning function, which comprises a voltage acquisition module, a current acquisition module, a residual current acquisition module, a metering module and an MCU intelligent control module, wherein the voltage and current acquisition module respectively acquires voltage and current signals of each phase line in an electric loop measured by the intelligent ammeter; voltage acquisition module, current acquisition module, residual current acquisition module are respectively with the signal of telecommunication of gathering separately sending into metering module, calculate by metering module and obtain electric quantity, return circuit current fundamental wave and harmonic, residual current fundamental wave and harmonic, calculate in the MCU intelligence control module that calculation module, sudden change processing module carry out time integral and with corresponding threshold value comparison to metering module's computational result, the comparative result is exported early warning logic module, carry out the potential safety hazard by early warning logic module and judge and the early warning.
Description
Technical Field
The invention relates to the field of intelligent electric meters, in particular to an intelligent electric meter with an early warning function.
Background
The electric meter is a short for electric energy meter, is an instrument for measuring electric energy, and is an instrument for measuring various electrical quantities. With the rapid development of global power applications and smart grids, the demand for smart meters is increasing day by day. The intelligent electric meter is an intelligent terminal of an intelligent power grid and has the functions of measuring electricity consumption, storing electricity consumption information, preventing electricity theft and the like. Besides the intelligent electric meters installed in the power supply system, the multifunctional electric meter is also one of the intelligent electric meters and is widely used in the fields of station power and civil power. The multifunctional electric power instrument can complete electric quantity measurement, electric energy metering, data display, acquisition and transmission, and is widely applied to electric energy measurement and management examination in substation automation, distribution automation, intelligent buildings and enterprises.
With the large-scale popularization of electric power applications, the number of accidents such as electrical safety, electrical fire and the like also increases significantly. Particularly, in the current stage of China, the occurrence rate of electrical fire is high for a long time, the electrical fire accounts for about 30% of the total amount of the fire in China, the proportion of the electrical fire in the extremely large fire is up to 60%, and according to the introduction of fire headquarters in Anhui province, casualty fire accidents are basically caused by the electrical fire because the electrical fire has the characteristics of strong concealment, quick combustion and frequent occurrence at night, and victims do not have enough escape time.
The electrical insulation aging is a main reason for generating electrical faults, safety accidents and electrical fires, can directly cause serious hidden dangers such as electric leakage, grounding and even short circuit, and statistics shows that 80-90% of electrical faults are directly and indirectly caused by the electrical insulation aging.
The government of China sets up the technical standard for monitoring the electric fire from 2005, and a large number of related products are already in practical use, but the occurrence rate of the electric fire is not effectively reduced, and the proportion of the electric fire in the total number of the fire is maintained at about 30% for years. In developed countries such as europe, america and japan, the occurrence rate of electrical fires has been greatly reduced by popularizing and promoting electrical fire monitoring technologies and products, and the proportion of electrical fires in japan in the total number of fires is currently less than 3%.
According to introduction of fire-fighting headquarters in Jiangsu province, 95% of installed residual current type electric fire monitoring systems are practically abandoned. The reason for this is that the prior art is relatively backward, for example, the parts of residual current such as resistance and sensitivity cannot be distinguished, government authorities force installation and use in business places such as markets, and these places have more sensitive load devices such as elevators and variable frequency lighting, and the sensitive residual current belongs to normal parameters, and generally does not cause fire, but causes a large amount of false alarms. Residential houses are places where such electrical fire monitoring products need to be used, and the like are not enforced, and therefore effective popularization and installation are not achieved. The power supply department mainly focuses on the power supply and meter reading system and is not willing to pay money to popularize the electric fire monitoring system. In fact, the electrical fire monitoring technology standard and the prior art products in China are relatively lagged behind, and the competent departments are lack of promotion power.
The intelligent electric meter technology and functions in the prior art are still embodied in measurement, management and centralized meter reading of electric energy data, and effective comprehensive monitoring, early warning and prevention of electrical safety hidden dangers such as electrical insulation aging, fault electric arcs, residual current type electrical fire and the like are lacked.
Disclosure of Invention
The invention aims to provide an intelligent ammeter with an early warning function, and the intelligent ammeter aims to solve the problem that in the prior art, the intelligent ammeter is difficult to monitor, early warn and prevent electrical safety hidden dangers including electrical insulation aging, fault electric arcs and residual current type electrical fire hidden dangers.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the utility model provides a smart electric meter with early warning function, includes the ammeter body, its characterized in that: still include electric quantity collection module, metering module, MCU intelligent control module, network communication module, wherein:
the electric quantity acquisition module acquires voltage, current and residual current signals of the electric loop;
the voltage and the current acquired by the electric quantity acquisition module are sent to the metering module, the metering module processes and calculates voltage and current signals to obtain related electric parameters of the ammeter body including the voltage, the current, a phase angle, the frequency, the power and the electric energy, and then the electric parameters are sent to the MCU intelligent control module;
the MCU intelligent control module also acquires the current and the residual current acquired by the electric quantity acquisition module;
the MCU intelligent control module is connected with the network communication module and externally transmits data;
the program is provided with calculation engineering module, sudden change processing module, early warning logic module in the MCU intelligence accuse module, wherein:
the calculation programming module obtains loop current harmonic waves and residual current harmonic waves according to the current and the residual current and sends the loop current harmonic waves and the residual current harmonic waves to the mutation processing module;
the calculation engineering module is used for respectively integrating the loop current harmonic and the residual current harmonic with respect to time to obtain loop current harmonic time integral parameters and residual current harmonic time integral parameters of each time period, and respectively sending the loop current harmonic time integral parameters and the residual current harmonic time integral parameters to the mutation processing module;
finding out the loop current harmonic and residual current harmonic values with mutation by a mutation processing module, integrating the loop current harmonic and residual current harmonic with mutation with time from the beginning of mutation to the end of mutation to obtain loop current harmonic time integral parameters and residual current harmonic time integral parameters of a mutation time period, and respectively sending the loop current harmonic time integral parameters and residual current harmonic time integral parameters into an early warning logic module;
in the early warning logic module, a loop current harmonic threshold value and a residual current harmonic threshold value are set, loop current harmonic time integration threshold values with different time scales are set, and residual current harmonic time integration threshold values with different time scales are set;
in the early warning logic module, if the loop current harmonic value or the residual current harmonic value is larger than the corresponding threshold value and appears intermittently, the early warning logic module judges that a phase line fault arc or a ground fault arc exists and carries out early warning and alarming processing;
in the early warning logic module, the set time integral threshold value of the corresponding time scale is calculated and converted into the time integral threshold value of the same time length according to the time length of the mutation time period; and if the loop current harmonic time integral parameter and the residual current harmonic time integral parameter in the sudden change time period are larger than the corresponding time integral threshold values with the same time length and appear intermittently, determining that the series-parallel fault electric arc or the ground fault electric arc exists, and performing emergency alarm processing.
The utility model provides an intelligent ammeter with early warning function which characterized in that: the electric quantity acquisition module is used for a single-phase electric loop, acquires voltage, current and residual current signals of the single-phase loop before entering a load, and sends the signals to the metering module;
the metering module calculates voltage, current and residual current signals to obtain related parameters, and sends the related parameters to the MCU intelligent control module;
the intelligent control module of the MCU is used for calculating a programming module, calculating resistance residual current and insulation conductance values according to related parameters, and sending the insulation conductance values and the resistance residual current values to the mutation processing module;
in the calculation program module, the insulation conductance and the resistance residual current are respectively integrated with respect to time to obtain insulation conductance time integration parameters and resistance residual current time integration parameters of each time period, and the insulation conductance time integration parameters and the resistance residual current time integration parameters are respectively sent to the early warning logic module;
finding out an insulation conductance value and a resistance residual current value which generate mutation in the mutation processing module, integrating the insulation conductance value and the resistance residual current value with time from the beginning to the end of mutation respectively to obtain an insulation conductance time integral parameter and a resistance residual current time integral parameter in a mutation time period, and then respectively sending the insulation conductance time integral parameter and the resistance residual current time integral parameter into an early warning logic module;
in the early warning logic module, insulation conductance time integral threshold values with different time scales and resistive residual current time integral threshold values with different time scales are preset;
in the early warning logic module, comparing the insulation conductance time integral parameter of each time period with a corresponding threshold value, if the insulation conductance time integral parameter is greater than the corresponding threshold value, judging that the corresponding time period has electrical insulation potential safety hazard by the early warning logic module, and performing early warning processing; aiming at the insulation conductance time integral parameter of the mutation time period, converting a preset corresponding time integral threshold value into an insulation conductance time integral threshold value with the same time length as the mutation time period, and then carrying out comparison judgment and early warning processing;
in the early warning logic module, comparing the resistive residual current time integral parameter of each time period with a corresponding threshold value, if the resistive residual current time integral parameter is greater than the corresponding threshold value, judging that electric leakage related to the potential safety hazard of the electrical fire exists in the corresponding time period by the early warning logic module, and performing early warning processing; and aiming at the time integral parameter of the resistive residual current of the sudden change time period, converting a preset corresponding time integral threshold value into a time integral threshold value of the resistive residual current with the same time length as the sudden change time period, and then carrying out comparison judgment and early warning processing.
The utility model provides an intelligent ammeter with early warning function which characterized in that: the intelligent control module of the MCU is used for a single-phase electric loop, the intelligent control module of the MCU is used for calculating an engineering module, further calculating to obtain an insulation resistance value according to related parameters, and sending the insulation resistance value to the early warning logic module;
an insulation resistance threshold value is preset in the early warning logic module;
and in the early warning logic module, the insulation resistance value is compared with the insulation resistance threshold value, if the insulation resistance value is larger than the insulation resistance threshold value, the single-phase electric loop is judged to have potential electrical insulation hazards, and early warning and warning processing are carried out.
The utility model provides an intelligent ammeter with early warning function which characterized in that: the calculation engineering module calculates according to the residual current to obtain a residual current fundamental wave numerical value, and sends the residual current fundamental wave numerical value to the mutation processing module and the early warning logic module;
finding out the residual current fundamental wave numerical value with mutation by the mutation processing module, integrating the residual current fundamental wave numerical value with time from the beginning of mutation to the end of mutation to obtain the residual current fundamental wave time integral parameter of the mutation time period, and sending the residual current fundamental wave time integral parameter into the early warning logic module;
a residual current fundamental wave threshold value and residual current fundamental wave time integral threshold values with different time scales are preset in the early warning logic module;
in the early warning logic module, the residual current fundamental wave value of each time period is compared with a corresponding threshold value, if the residual current fundamental wave value is larger than the corresponding threshold value, the residual current electrical fire hazard in the time period is judged to exist, and early warning processing is carried out;
in the early warning logic module, comparing residual current fundamental wave time integral parameters of each time period with corresponding threshold values, if the residual current fundamental wave time integral parameters are larger than the corresponding threshold values, judging that residual current type electric fire hazards exist in the time period, and performing early warning processing; and aiming at the residual current fundamental wave time integral parameter of the sudden change time period, converting the preset time integral threshold value of the corresponding time scale into the time integral threshold value with the same duration as the sudden change time period, and then performing comparison judgment and early warning processing.
The utility model provides an intelligent ammeter with early warning function which characterized in that: the trip control module is arranged and is connected into a corresponding electrical loop to control tripping and power off, the signal input end of the trip control module is connected with the MCU intelligent control module, a program early warning logic module in the MCU intelligent control module generates a tripping control instruction signal to be sent to the trip control module when detecting serious hidden danger, and the tripping control module carries out power off protection after receiving the tripping control instruction signal. .
The invention has the beneficial effects that:
the monitoring alarm is developed into the monitoring early warning, which is a necessary trend of the development of electrical safety. The Ann Commission of the 5-month State Council in 2017 is from 5 months in 2017 to 4 months in 2020, and forms a special 'comprehensive electrical fire control leadership group' from the State Council to each province, city and county in the period of three years, wherein leaderships of national grid companies and southern grid companies are important members of all levels of leaderships groups.
The intelligent electric meter with the early warning function is developed aiming at the electric fire monitoring and early warning function, the intelligent electric meter is used as a carrier, and the method is feasible for implementing the comprehensive treatment of the electric fire in a large range through a national network and a south network at present.
The monitoring and early warning of early weak hidden dangers of electrical safety is not suitable for the existing safe electrical and electrical fire monitoring and warning technology which is characterized in that transient electrical parameters such as voltage, current, residual current and the like are compared with a preset threshold value, because the numerical values of the single transient parameters corresponding to the early weak hidden dangers are all lower than or far lower than the warning threshold value. In addition, in the aspect of time, the duration of the continuous storage time of the early electrical potential safety hazard is far longer than the duration of the existence of the later serious potential safety hazard, so that the total amount of early potential safety hazard data is huge, and a large amount of storage equipment and bandwidth flow are wasted when a large amount of data is locally stored or sent to a cloud platform.
The invention adopts the integration mode data aggregation of the weak signal parameters of the relevant electrical safety to the time, greatly reduces the effective data volume of early weak hidden danger and improves the precision. The invention further adopts mutation time integral parameters, has the significance of tracking and obtaining integral parameters related to the complete process of the mutation event, and can accurately master the hidden danger degree of the related electrical safety mutation event.
The invention combines the existing three-phase electric meter main body, judges the electrical safety hidden danger through current harmonic waves, residual current fundamental waves and harmonic waves and time integral parameters thereof, and further monitors and pre-warns the electrical safety hidden danger based on the residual current type electrical fire hidden danger and fault electric arc hidden danger which are main contents.
The method is combined with the existing single-phase electric meter main body, aiming at a single-phase electric loop, the electric insulation hidden danger is detected on line through multiple angles such as insulation resistance, insulation conductance, resistive residual current and the like, and further data aggregation is carried out by adopting resistive residual current and insulation conductance time integral parameters of all time periods including sudden change time periods.
According to the invention, the function of the electric meter is expanded from electricity consumption metering to a safety early warning type single-phase intelligent electric meter with contents of electric insulation aging hidden danger, electric fire hidden danger monitoring and fault electric arc monitoring, and an internet of things network communication module connected with a cloud platform is further equipped, so that a new generation of internet of things safety early warning type internet of things single-phase intelligent electric meter is formed.
The method can directly judge the existence of potential safety hazards of the abnormal time integral parameters which are larger than the threshold value. And for the abnormal time integral parameter smaller than the threshold, the sudden change time integral parameter is adopted, and the sudden change time period integral parameter with the sudden change is found in the time period corresponding to the abnormal time integral parameter, so that the time for potential safety hazards to appear can be further positioned, and the electric equipment used in the time period is correspondingly checked aiming at the sudden change parameter time period, thereby being beneficial to finding potential safety hazard equipment and improving the judgment precision and accuracy.
The invention selects the resistive residual current as the monitoring key point, because most of the capacitive residual current and inductive residual current generated by the distributed capacitance and the inductance are evenly distributed along the electric loop cable and usually do not directly cause heating, and most of the resistive residual current leaks through a few leakage points and directly causes heating.
The invention monitors the phase line fault arc and the ground fault arc through the loop current harmonic wave and the residual current harmonic wave under the condition of adding a small amount of hardware structures. In the invention, intermittent harmonic current is taken as a key point, because a large amount of middle-low-grade and even inferior variable-frequency energy-saving electric equipment exists in China at the present stage, the harmonic current is released to an equipment shell and a protective ground wire, and stable continuous large-current harmonic waves and harmonic residual currents are formed. The continuous and stable harmonic current and harmonic residual current can directly interfere with the judgment of the fault arc, but the fault arc has intermittent time sequence characteristics, and the practicability of fault arc detection is greatly improved by taking the intermittent time sequence characteristics as a criterion. Harmonic currents are also referred to as current harmonics and harmonic residual currents are also referred to as residual current harmonics in the present document;
the tripping control module is arranged, so that the occurrence and the expansion of electrical faults and electrical fire disasters are prevented through tripping power-off protection aiming at finding serious potential safety hazards such as electrical insulation, resistive residual current, fault electric arcs and the like.
Drawings
Fig. 1 is a schematic block diagram of the structure of the present invention.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
Example 1: as shown in fig. 1, a smart electric meter with early warning function, including the ammeter body, still include electric quantity collection module, metering module, MCU intelligent control module, network communication module, wherein:
the electric quantity acquisition module acquires voltage, current and residual current signals of the electric loop; the electric quantity acquisition module comprises a voltage acquisition processing circuit, a current acquisition processing circuit and a residual current acquisition processing circuit;
the electric quantity acquisition module is connected with an input port of the metering module and sends voltage, current and residual current signals of the electric loop to the metering module;
in this embodiment, for a three-phase electrical loop, the metering module adopts a scheme of a double-RN 8302 electric energy metering chip, the RN8302 chip is a three-phase electric energy metering chip with harmonic monitoring, but an internal N-phase current processing part of the metering module has no harmonic calculation function and can only obtain an effective value, but the chip is low in cost, and a single-phase electric energy metering chip at the present stage generally has no harmonic calculation function, so that a single RN8302 is adopted in the scheme of the invention to acquire a residual current signal.
Thus, in this embodiment, the UA, UB, UC, IA, IB, and IC analog input ports of one main RN8302 chip are respectively connected to the sampling processing circuits of the three-phase voltage and the three-phase current in the electric quantity acquisition module; the MCU intelligent control module obtains relevant electrical data including voltage, current, power, electric energy, frequency, phase angle and the like through the main RN8302 chip, and the conventional ammeter function is realized through calculation processing;
meanwhile, the MCU intelligent control module also obtains fundamental wave and harmonic wave of loop voltage and fundamental wave and harmonic wave related parameters of current through the main RN8302 chip;
any one of analog input ports IA, IB and IC of the other auxiliary RN8302 chip is connected with a residual current sampling processing circuit in the electric quantity acquisition module;
the RN8302 chip is connected with a corresponding interface of the MCU intelligent control module through an SPI or UART data communication interface; the MCU intelligent control module obtains residual current fundamental waves and harmonic numerical values thereof through the auxiliary RN8302 chip.
In this embodiment, different with the current ammeter scheme including current smart electric meter, the MCU intelligence accuse module obtains return circuit phase current harmonic numerical value and residual current harmonic numerical value through metering module to further detect and calculate, judge trouble electric arc hidden danger.
MCU intelligence accuse module is connected with thing networking communication submodule piece, carries out external data transmission, wherein:
one or more of WIFI, Bluetooth, GPRS and 4G, NB-IoT are adopted to be directly connected and communicated with the Internet cloud platform, and the Internet of things communication sub-module is indirectly connected and communicated with the Internet cloud platform by adopting local RS485/CAN communication;
the MCU intelligent control module in the embodiment is also connected with an infrared communication sub-module;
the program is provided with calculation engineering module, sudden change processing module, early warning logic module in the MCU intelligence accuse module, wherein:
the calculation engineering module obtains loop current harmonic waves and residual current harmonic waves through the metering module and sends the loop current harmonic waves and the residual current harmonic waves to the mutation processing module; respectively integrating the loop current harmonic and the residual current harmonic for time to obtain loop current harmonic time integration parameters and residual current harmonic time integration parameters of each time period, and sending the loop current harmonic time integration parameters and the residual current harmonic time integration parameters to a mutation processing module;
the time periods of the invention are generally based on the whole time periods of minutes, hours, days, months and the like;
finding out the loop current harmonic wave or the residual current harmonic wave parameter with mutation by a mutation processing module, integrating the loop current harmonic wave and the residual current harmonic wave with mutation to time from the beginning of mutation to the end of mutation to obtain the loop current harmonic wave time integral parameter and the residual current harmonic wave time integral parameter of a mutation time period, and respectively sending the loop current harmonic wave time integral parameter and the residual current harmonic wave time integral parameter to an early warning logic module;
in the early warning logic module, a loop current harmonic threshold value, a residual current harmonic threshold value, a loop current harmonic time integral threshold value and a residual current harmonic time integral threshold value of different time scales are respectively set; the different time scales of the invention are generally unit time with different lengths such as whole minute, hour, day, month and the like;
in the early warning logic module, if the loop current harmonic value or the residual current harmonic value is larger than the corresponding threshold value and appears intermittently, the early warning logic module judges that a phase line fault arc or a ground fault arc exists and carries out early warning and alarming processing;
the harmonic intermittence refers to the situation that the harmonic value of the current of a phase line of a loop or the harmonic value of the residual current exceeds the corresponding harmonic threshold value and returns to be lower than the threshold value within the second-level time, and the harmonic value exceeds the threshold value within the second-level time and repeatedly appears, and an early warning logic module sets an intermittence mark in a program;
in the early warning logic module, the set time integral threshold value of the corresponding time scale is calculated and converted into the time integral threshold value of the same time length according to the time length of the mutation time period; and if the loop current harmonic time integral parameter and the residual current harmonic time integral parameter in the sudden change time period are larger than the corresponding time integral threshold values with the same time length and appear intermittently, determining that the series-parallel fault electric arc or the ground fault electric arc exists, and performing emergency alarm processing.
In this embodiment, the computation engineering module integrates the residual current fundamental wave value with respect to time through the residual current fundamental wave value obtained by the metering module to obtain a residual current fundamental wave time integration parameter of each time period, and sends the residual current fundamental wave time integration parameter to the mutation processing module and the early warning logic module;
finding out the residual current fundamental wave numerical value with mutation by the mutation processing module, integrating the residual current fundamental wave numerical value with time from the beginning of mutation to the end of mutation to obtain the residual current fundamental wave time integral parameter of the mutation time period, and sending the residual current fundamental wave time integral parameter into the early warning logic module;
residual current fundamental wave time integral threshold values with different time scales are preset in the early warning logic module, if the residual current fundamental wave time integral parameter of each time period is larger than the residual current fundamental wave time integral threshold value of the corresponding time scale, the existence of residual current type electric fire hazard in the time period is judged, and early warning processing is carried out; and aiming at the residual current fundamental wave time integral parameter of the sudden change time period, converting the preset time integral threshold value of the corresponding time scale into the time integral threshold value with the same duration as the sudden change time period, and then performing comparison judgment and early warning processing.
This embodiment sets up trip control module, control the trip outage in the corresponding electrical loop of access, and trip control module signal input part is connected with MCU intelligence control module, and the early warning logic module of procedure generates trip control command signal and sends to trip control module when detecting serious hidden danger in the MCU intelligence control module, carries out power protection after trip control command signal is received to trip control module.
Example 2: compared with the embodiment 1, the electric quantity acquisition module sends voltage and current signals of the electric loop to the metering module and sends residual current signals to the AD sub-module, wherein the AD sub-module is an analog quantity (AD) acquisition processing unit of a microcontroller in the MCU intelligent control module; handleResidual current acquisition processing circuitOne of the analog input pins of the ST32 series microprocessor connected to the MCU intelligent control module, such as AN 0;
in a calculation sub-process module of the MCU intelligent control module, calculating to obtain a phase current effective value and a residual current effective value numerical value through a root mean square algorithm, and obtaining a phase current fundamental wave and a residual current fundamental wave IS numerical value through Fourier calculation (FFT); and subtracting the fundamental wave value from each effective value to obtain a corresponding harmonic wave value (full harmonic wave), and obtaining phase current harmonic wave Ix and residual current harmonic wave Isx values.
The difference between the embodiment 2 and the embodiment 1 is that the embodiment 1 obtains the residual current fundamental wave and the residual current harmonic wave through a metering module, and the embodiment 2 obtains the loop residual current fundamental wave and the residual current harmonic wave through calculation by a microprocessor STM32 series microprocessor chip of an MCU intelligent control module.
Example 3: the utility model provides a smart electric meter is suitable for at single-phase electric loop with early warning function, includes the single-phase ammeter body that has zero live wire double-line structure, wherein: in the single-phase electric meter with the zero-live wire double-wire structure, the zero line connected with the electric loop is the independent zero line of the single-phase electric loop, and the zero-row terminal is not connected in the middle and is not connected with other lines in a mixed mode;
in the embodiment, for a single-phase electric loop, an electric quantity acquisition module acquires voltage, current and residual current signals of the single-phase electric loop; in order to directly obtain corresponding harmonic signals and parameter values through the metering module, and the acquisition precision of a general special metering chip is far higher than that of an analog quantity channel of a microcontroller chip, the metering module still adopts an RN8302 electric energy metering chip.
In this embodiment, the current collection module and the residual current collection module are connected to the corresponding input ports IA and IB of the RN8302 chip, respectively, and the voltage collection module for collecting single-phase voltage signals is connected to the corresponding input ports UA and UB of the RN8302 chip.
The RN8302 chip is connected with the MCU intelligent control module SPI data communication interface through the SPI data communication interface. The MCU intelligent control module obtains a voltage U and a harmonic signal Ux thereof, a loop current fundamental wave I and a harmonic Ix thereof, a residual current fundamental wave Is and a harmonic signal Isx thereof, single-phase power P and electric energy through an RN8302 chip in the metering module; the voltage and the residual current of UB and IB ports connected to the RN8302 chip B phase obtain leakage power and leakage electric energy related to the residual current, and the leakage active power Ps is obtained through refinement; and further obtaining an active part and a reactive part of the residual current, wherein the active part of the residual current is a resistive residual current.
In a calculation sub-process module of the MCU intelligent control module, calculating by a root mean square algorithm to obtain an effective value of a residual current effective value, and calculating by Fourier transform (FFT) to obtain a value of a residual current fundamental wave Is; and subtracting the effective value from the fundamental wave value to obtain a corresponding harmonic value (full harmonic) and obtain a residual current harmonic Isx value.
In the calculation program module, the real part and the imaginary part of the impedance can be calculated through a two-point product algorithm or an FFT Fourier algorithm, wherein the real part of the impedance is an insulation resistance Rs, and the reciprocal of the insulation impedance is an insulation conductance Gs; similarly, the real part of the residual current Is calculated to obtain the resistive residual current IsR。
In the calculation program module, an insulation conductance value and a resistance residual current value are sent to the mutation processing module;
in the calculation program module, the insulation conductance and the resistance residual current are respectively integrated with respect to time to obtain insulation conductance time integration parameters and resistance residual current time integration parameters of each time period, and the obtained parameters are respectively sent to the early warning logic module;
finding out an insulation conductance value and a resistance residual current value which generate mutation in the mutation processing module, integrating the insulation conductance value and the resistance residual current value with time from the beginning to the end of mutation respectively to obtain an insulation conductance time integral parameter and a resistance residual current time integral parameter in a mutation time period, and then respectively sending the insulation conductance time integral parameter and the resistance residual current time integral parameter into an early warning logic module;
the early warning logic module is preset with insulation conductance time integral threshold values and resistive residual current time integral threshold values of different time scales;
in the early warning logic module, comparing the insulation conductance time integral parameter of each time period with a corresponding threshold value, if the insulation conductance time integral parameter is greater than the corresponding threshold value, judging that the corresponding time period has electrical insulation potential safety hazard by the early warning logic module, and performing early warning processing; aiming at the insulation conductance time integral parameter of the mutation time period, converting a preset corresponding time integral threshold value into an insulation conductance time integral threshold value with the same time length as the mutation time period, and then carrying out comparison judgment and early warning processing;
in the early warning logic module, comparing the resistive residual current time integral parameter of each time period with a corresponding threshold value, if the resistive residual current time integral parameter is greater than the corresponding threshold value, judging that electric leakage related to the potential safety hazard of the electrical fire exists in the corresponding time period by the early warning logic module, and performing early warning processing; and aiming at the time integral parameter of the resistive residual current of the sudden change time period, converting a preset corresponding time integral threshold value into a time integral threshold value of the resistive residual current with the same time length as the sudden change time period, and then carrying out comparison judgment and early warning processing.
In this embodiment, through the combination of the voltage of the single-phase electric loop and the residual current vector, the calculation program module calculates through the electric quantity acquisition module to obtain the leakage active power, further calculates to obtain an insulation resistance value, and sends the insulation resistance value to the early warning logic module; and presetting an insulation resistance threshold value in the early warning logic module, comparing the insulation resistance value with the insulation resistance threshold value, judging whether the potential electrical insulation hazard exists, and early warning.
Example 4: the utility model provides an intelligent ammeter with early warning function is suitable for in single-phase electric loop, is different from embodiment 3, adopts conventional single-phase electric energy metering chip among the metering module, and this embodiment adopts RN8209 single-phase electric energy metering chip, and single-phase electric energy metering chip does not all take the harmonic to calculate the function at present.
In this embodiment, the voltage and current acquisition processing circuit is connected to the UA and IA corresponding input ports of the RN8209 chip, and the voltage and current acquisition processing circuit is also connected to different analog input pins of the ST32 series microprocessor in the MCU intelligent control module, such as AN1 and AN 2; handleResidual current acquisition processing circuitOther analog input pins of the ST32 series microprocessor connected to the MCU intelligent control module, such as AN 0; voltage, current and residual current signals are all sent to an AD submodule, wherein an ST32 series microprocessor synchronously acquires the voltage and residual current signals;
the RN8209 chip is connected with a corresponding communication interface of the MCU intelligent control module through an SPI or UART communication interface, and the MCU intelligent control module obtains voltage U, current I, phase angle, frequency, power, electric energy and other conventional electric meter data through the RN8209 chip in the metering module.
In a calculation sub-process module of the MCU intelligent control module, phase voltage effective values, phase current effective values and residual current effective values are calculated and obtained through a root mean square algorithm, and phase voltage fundamental waves, phase current fundamental waves and residual current fundamental waves Is values are obtained through Fourier calculation (FFT); and subtracting the fundamental wave value from each effective value to obtain corresponding harmonic wave value (full harmonic wave) and phase voltage harmonic wave, phase current harmonic wave Ix and residual current harmonic wave Isx values.
In the calculation equation module, the real part and the imaginary part of the impedance can be calculated by a two-point product algorithm or an FFT Fourier algorithm, wherein the real part of the impedance isInsulation resistance Rs, the reciprocal of which is insulation conductance Gs; similarly, the real part of the residual current Is calculated to obtain the resistive residual current IsR。
In each embodiment of the invention, the voltage acquisition module is a voltage transformer or a resistance grid; the current acquisition module is a current transformer or a current divider; the residual current acquisition module is a punching precision current transformer.
In the present invention, current harmonics are also referred to as harmonic currents, and residual current harmonics are also referred to as harmonic residual currents, and are generally total harmonic values unless otherwise specified.
The embodiments of the specific implementation mode of the invention comprise:
the MCU intelligent control module is connected with an RTCS clock module;
the MCU intelligent control module is connected with an ESAM encryption module;
the MCU intelligent control module is connected with a storage module, including but not limited to an EEPROM or FLASH memory;
the MCU intelligent control module is connected with the human-computer interface module and comprises keys, an indicator light and an LCD/LED display sub-module.
Claims (5)
1. The utility model provides a smart electric meter with early warning function, includes the ammeter body, its characterized in that: still include electric quantity collection module, metering module, MCU intelligent control module, network communication module, wherein:
the electric quantity acquisition module acquires voltage, current and residual current signals of the electric loop;
the voltage and the current acquired by the electric quantity acquisition module are sent to the metering module, the metering module processes and calculates voltage and current signals to obtain related electric parameters of the ammeter body including the voltage, the current, a phase angle, the frequency, the power and the electric energy, and then the electric parameters are sent to the MCU intelligent control module;
the MCU intelligent control module also acquires the current and the residual current acquired by the electric quantity acquisition module;
the MCU intelligent control module is connected with the network communication module and externally transmits data;
the program is provided with calculation engineering module, sudden change processing module, early warning logic module in the MCU intelligence accuse module, wherein:
the calculation programming module obtains loop current harmonic waves and residual current harmonic waves according to the current and the residual current and sends the loop current harmonic waves and the residual current harmonic waves to the mutation processing module;
the calculation engineering module is used for respectively integrating the loop current harmonic and the residual current harmonic with respect to time to obtain loop current harmonic time integral parameters and residual current harmonic time integral parameters of each time period, and respectively sending the loop current harmonic time integral parameters and the residual current harmonic time integral parameters to the mutation processing module;
finding out the loop current harmonic and residual current harmonic values with mutation by a mutation processing module, integrating the loop current harmonic and residual current harmonic with mutation with time from the beginning of mutation to the end of mutation to obtain loop current harmonic time integral parameters and residual current harmonic time integral parameters of a mutation time period, and respectively sending the loop current harmonic time integral parameters and residual current harmonic time integral parameters into an early warning logic module;
in the early warning logic module, a loop current harmonic threshold value and a residual current harmonic threshold value are set, loop current harmonic time integration threshold values with different time scales are set, and residual current harmonic time integration threshold values with different time scales are set;
in the early warning logic module, if the loop current harmonic value or the residual current harmonic value is larger than the corresponding threshold value and appears intermittently, the early warning logic module judges that a phase line fault arc or a ground fault arc exists and carries out early warning and alarming processing;
in the early warning logic module, the set time integral threshold value of the corresponding time scale is calculated and converted into the time integral threshold value of the same time length according to the time length of the mutation time period; and if the loop current harmonic time integral parameter and the residual current harmonic time integral parameter in the sudden change time period are larger than the corresponding time integral threshold values with the same time length and appear intermittently, determining that the series-parallel fault electric arc or the ground fault electric arc exists, and performing emergency alarm processing.
2. The smart meter with the early warning function according to claim 1, wherein: the electric quantity acquisition module is used for a single-phase electric loop, acquires voltage, current and residual current signals of the single-phase loop before entering a load, and sends the signals to the metering module;
the metering module calculates voltage, current and residual current signals to obtain related parameters, and sends the related parameters to the MCU intelligent control module;
the intelligent control module of the MCU is used for calculating a programming module, calculating resistance residual current and insulation conductance values according to related parameters, and sending the insulation conductance values and the resistance residual current values to the mutation processing module;
in the calculation program module, the insulation conductance and the resistance residual current are respectively integrated with respect to time to obtain insulation conductance time integration parameters and resistance residual current time integration parameters of each time period, and the insulation conductance time integration parameters and the resistance residual current time integration parameters are respectively sent to the early warning logic module;
finding out an insulation conductance value and a resistance residual current value which generate mutation in the mutation processing module, integrating the insulation conductance value and the resistance residual current value with time from the beginning to the end of mutation respectively to obtain an insulation conductance time integral parameter and a resistance residual current time integral parameter in a mutation time period, and then respectively sending the insulation conductance time integral parameter and the resistance residual current time integral parameter into an early warning logic module;
in the early warning logic module, insulation conductance time integral threshold values with different time scales and resistive residual current time integral threshold values with different time scales are preset;
in the early warning logic module, comparing the insulation conductance time integral parameter of each time period with a corresponding threshold value, if the insulation conductance time integral parameter is greater than the corresponding threshold value, judging that the corresponding time period has electrical insulation potential safety hazard by the early warning logic module, and performing early warning processing; aiming at the insulation conductance time integral parameter of the mutation time period, converting a preset corresponding time integral threshold value into an insulation conductance time integral threshold value with the same time length as the mutation time period, and then carrying out comparison judgment and early warning processing;
in the early warning logic module, comparing the resistive residual current time integral parameter of each time period with a corresponding threshold value, if the resistive residual current time integral parameter is greater than the corresponding threshold value, judging that electric leakage related to the potential safety hazard of the electrical fire exists in the corresponding time period by the early warning logic module, and performing early warning processing; and aiming at the time integral parameter of the resistive residual current of the sudden change time period, converting a preset corresponding time integral threshold value into a time integral threshold value of the resistive residual current with the same time length as the sudden change time period, and then carrying out comparison judgment and early warning processing.
3. The smart meter with the early warning function according to claim 2, wherein: the intelligent control module of the MCU is used for a single-phase electric loop, the intelligent control module of the MCU is used for calculating an engineering module, further calculating to obtain an insulation resistance value according to related parameters, and sending the insulation resistance value to the early warning logic module;
an insulation resistance threshold value is preset in the early warning logic module;
and in the early warning logic module, the insulation resistance value is compared with the insulation resistance threshold value, if the insulation resistance value is larger than the insulation resistance threshold value, the single-phase electric loop is judged to have potential electrical insulation hazards, and early warning and warning processing are carried out.
4. The smart meter with the early warning function according to claim 1, wherein: the calculation engineering module calculates according to the residual current to obtain a residual current fundamental wave numerical value, and sends the residual current fundamental wave numerical value to the mutation processing module and the early warning logic module;
finding out the residual current fundamental wave numerical value with mutation by the mutation processing module, integrating the residual current fundamental wave numerical value with time from the beginning of mutation to the end of mutation to obtain the residual current fundamental wave time integral parameter of the mutation time period, and sending the residual current fundamental wave time integral parameter into the early warning logic module;
a residual current fundamental wave threshold value and residual current fundamental wave time integral threshold values with different time scales are preset in the early warning logic module;
in the early warning logic module, the residual current fundamental wave value of each time period is compared with a corresponding threshold value, if the residual current fundamental wave value is larger than the corresponding threshold value, the residual current electrical fire hazard in the time period is judged to exist, and early warning processing is carried out;
in the early warning logic module, comparing residual current fundamental wave time integral parameters of each time period with corresponding threshold values, if the residual current fundamental wave time integral parameters are larger than the corresponding threshold values, judging that residual current type electric fire hazards exist in the time period, and performing early warning processing; and aiming at the residual current fundamental wave time integral parameter of the sudden change time period, converting the preset time integral threshold value of the corresponding time scale into the time integral threshold value with the same duration as the sudden change time period, and then performing comparison judgment and early warning processing.
5. The smart meter with the early warning function according to any one of claims 1 to 4, wherein: the trip control module is arranged and is connected into a corresponding electrical loop to control tripping and power off, the signal input end of the trip control module is connected with the MCU intelligent control module, a program early warning logic module in the MCU intelligent control module generates a tripping control instruction signal to be sent to the trip control module when detecting serious hidden danger, and the tripping control module carries out power off protection after receiving the tripping control instruction signal.
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| CN110286348A (en) * | 2019-06-19 | 2019-09-27 | 国网湖北省电力有限公司宜昌供电公司 | The method for early warning of gauge table |
| CN110455333A (en) * | 2019-08-14 | 2019-11-15 | 郑州今迈衡器有限公司 | A kind of metering device that transfinites based on network transmission |
| CN110716155B (en) * | 2019-10-24 | 2022-05-06 | 国网上海市电力公司 | Low-voltage power supply loop abnormal working condition perception algorithm and device |
| CN110794199A (en) * | 2019-11-15 | 2020-02-14 | 苏师大半导体材料与设备研究院(邳州)有限公司 | Multifunctional electric power instrument |
| CN110907736A (en) * | 2019-12-06 | 2020-03-24 | 浩云科技股份有限公司 | Electrical safety monitoring system with multi-path electrical parameter monitoring and multi-path ignition detection |
| CN112034247A (en) * | 2020-07-17 | 2020-12-04 | 宁波三星医疗电气股份有限公司 | Fault recording method of electric energy meter and electric energy meter thereof |
| CN112098921B (en) * | 2020-09-17 | 2021-10-15 | 南方电网科学研究院有限责任公司 | Testing device, method and system for residual current monitoring and alarming function of electric energy meter |
| CN112098920B (en) * | 2020-09-17 | 2021-10-15 | 南方电网科学研究院有限责任公司 | Testing device, method and system for residual current monitoring function of intelligent electric energy meter |
| CN114088998A (en) * | 2021-11-23 | 2022-02-25 | 成都创立智能科技有限公司 | Electric safety early warning type smart electric meter |
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